1. Technical Field
The present invention relates, generally, to methods and apparatus for reflowing solder paste using a light source and, more particularly, to a movable head having a solder paste dispenser and a heat lamp mounted thereto for simultaneously applying a bead of solder paste to the leads of a microelectronic component mounted on a printed wiring board and heating the applied solder paste.
2. Background Art and Technical Problems
Presently known techniques for soldering high pin count, fine pitch surface mounted connectors to corresponding electrically conductive pads on a printed circuit board involve the use of hot bar soldering, focused light beam soldering using solder wire, hand soldering, and pre-soldered component soldering. While presently known soldering techniques generally provide good electrical contact between the component leads and the circuit board, these techniques are time consuming and cumbersome which tend to limit throughput.
Other known soldering techniques employ a stencil having cutouts located at the contacts of the printed circuit board, with the stencil being overlaid on to the circuit board. A dollop of solder paste is then applied to the stencil at one end of the circuit board, and thereafter, xe2x80x9csqueegeedxe2x80x9d to ensure that solder paste is applied to all of the electrical contacts (also referred to herein as xe2x80x9cpadsxe2x80x9d) to the cutouts in the stencil. After the stencil is removed, solder paste covers all of the contacts on the circuit board. The microelectronic components are then placed on the circuit board with the leads extending from the components placed in contact with the pre-soldered pads on the circuit board. Again, this technique is time consuming and cumbersome, and can result in electrical short circuits due to imprecise application of the solder, misalignment of the component parts on the circuit board, and the like.